Synthetic production of ammonia



June 24, 1930. R. s. RICHARDSON SYNTHETIC PRODUCTION OF AMMONIA Filed Feb. 26, 1927 ODO 00.0 0 v Doocowwowoaomv :a uuoonebvo Gas K- Patented June 24, 1930 UNITED STA-TES PATENT oFFlcE RALPH S. RICHARDSON, OF TEANECK, NEIN JERSEY, A/SSIGNOR TO CHEMICAL ENGI- NEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE SYNTHETIC PRODUCTION OF AMMONIA Application led February 26, 1927. Serial No.'171,144.

My invention relates p rticularly to improved methods for se arating ammonia from the synthesized ammonia-containing gases. v

In the synthesis of ammonia at high pressure, the removing of the relatively small por- 'tion of ammonia formed during passage of nitrogen-hydrogen gases overa catalyst from the uncombined nitrogen-hydrogen gases has been accomplished in several ways.

One method is to wash out the ammonia Y by direct contact with water or other solvents.

Such method is open to objections in that the uncombined gases leave the ammonia removal apparatus saturated with the solvent. An-

other method is to condense the ammonia by indirect cooling with water or other refrigerant whereby the heat from the synthesized gas mixture is transferred through a metal wall.

I have discovered that the gaseous am'- monia fraction may be removed eiiciently .from the synthesized gases by actual contact with refrigerated liquid ammonia.

Accordin to my invention, liquid ammonia, whic is the product obtained by liquefying ammonia gas, say at 0 C. and at a lower temperature than the synthesized gases which are at room temperature about 30 C., is brought into direct actual and direct heat exchange relationship with these synthesized gases, such gases travelling in counter-current to the How of the liquefied ammonia, with the result that the liquid ammonia is warmed while the synthesized gases are cooled with a precipitation of their gaseous ammonia content. Such liquid ammonia may then be cooled back to its initial temperature either by water cooling or by expansion of the ammonia product, or by other known means, and thereafter used to efect further condensation in the continued cyclic processes of separation.

The accompanying drawings show in diagrammatic form an apparatus which is adapt` ed for carrying out the methods of my invention.

The synthesized ases from the converter enter the tower 1 t rough the pipe 2. The

50 tower 1 is filled with suitable packing 3 comprising broken pieces of glass or porcelain to present a surface-giving mass resting on the perforated grate 4. Such gases pass upwardly through the packing 3 in actual contact with a descending stream of relatively cooler liquid ammonia which enters the top of the tower 1 through the pipe 5. The gases leave the tower 1 through the pipe 6 and are returned to the converter. The liquid ammonia which drips through the packing 3 and grate 4 leaves the tower l by the pipe 7 connected with the pump 8 which-forces this liquid ammonia through the refrigerator tank 9 and the liquid ammonia re-enters the top of the tower 1 through the pipe 5 as has been hereinbefore described. Such ammonia as has been condensed from the synthesized gases is removed from the tower 1 by the pipe 10.

I do not wish to restrict my improved methods to the particular apparatus shown and described as there are various ways of applying my invention.

For example, the refrigerator tank 9 may be placed on either side of the pump 8 in the circulating system for the liquid ammonia. Again water or brine may be used in the refrigerator tank 9, or the ammonia condensate withdrawn from the tower 1 through the pipe may be expanded and used for refrigeraion.

Another feature of my improved ammonia separation methods consists in withdrawing both the circulating liquid ammonia and the fresh condensate from the bottom of the tower 1 throughthe pipe 10 to another vessel, and then reducing the pressure to permit the ammonia to evaporate as a gas which is taken from the vessel with the result that the liquid ammonia stored in the vessel is put into' circulation and is directly cooled in transit through the circulating system rst described and is returned to the top of the tower 1.

I claim as my invention 1. In the synthetic production of ammonia, the step for separating ammonia from synthesized ammonia-containing gases which consists in passing the synthesized gases after catalysis in actual contact with,-

' mass, simultaneously passing the s'ynthe but -in counter-current flow to, relatively cooler liquid ammonia in circulation.

2. In the synthetic production of ammonia, the method for separatingammonia from/synthesized ammonia-containing ases which comprises distributing relat1vely' cooler liquid ammonia over asurface-giving sized gases after catalysis in actual contact with the liquid ammonia through the mass in counter-current to the iiow of said liquid ammonia, and removing the ammonia condensateformed.

3. In the synthetic production` of ammonia, the method for separating ammonia fromy synthesized ammonia-containing gases distributing relatively which comprises cooler liquid ammonia over a surface-givin mass, simultaneously passing the synthesize gases after catalysis through the mass in actual contact with the li uid amomnia, but in counter-current to the ow of such liquid ammonia in circulation.

4. In the synthetic production of ammonia, the steps for separating ammonia from synthesized ammonia-containing gases which comprise passing the synthesized gases after catalysis under pressure in actual contact with, but in counter-current flow to, relatively cooler liquid ammonia in circulation and then cooling such liquid ammonia to its initial temperature.

5. In the synthetic production of ammonia, the methodfor separating ammonia from synthesized ammonia-containing gases which comprises distributing relatively cooler liquid ammonia over a surface-giving mass, simultaneously passing the synthesized gases after catalysis in actual contact withv the liquid ammonia through the mass in counter-current to the How of said liquid ammonia, and removing the ammonia condensate formed while maintaining a continuous circulation of liquid ammonia in actual contact with the gases through the mass.

6. In the synthetic production of am-v monia, the steps for separating ammonia from synthesized ammonia-containing gases which comprise passing the synthesized gases after catalysis under pressure in actual contact with, but in counter-current low to, relatively cooler liquid ammonia in circulation and then cooling such liquid ammonia to its initial temperature while continuing its circulation in actual contact with said gases.

7 .l In the synthetic production of vammonia, the steps for separating ammonia from synthesized ammonia-containing gases which comprise passing the synthesized gases after catalysis under pressure in actual contact with, but in counter-current iiow of,

relatively cooler liquid ammonia in circulav tion, slmultaneously removln4 the ammoma condensate l1qu1d ammoma and reducmg 

